Executive order to blast jets defended

President Bush's order giving the military permission to shoot down any airplane that threatened the capital Tuesday apparently was an unprecedented decision by a U.S. president, experts said.

Officials have said the military did not shoot down any of the four hijacked jetliners. But the authorization to do so is within legal and ethical bounds, according to experts who cited the need to save the lives of hundreds or thousands of people on the ground.

On Sunday, Vice President Dick Cheney said the president gave the Air Force the go-ahead to destroy any airliner that threatened the capital or did not respond to warnings to avoid Washington airspace after the initial attacks. Bush later confirmed the decision.

"The president made the decision ... that if the plane would not divert, if they wouldn't pay any attention to instructions to move away from the city, as a last resort, our pilots were authorized to take them out," Cheney said on NBC's "Meet the Press."

The last hijacked jetliner in the air Tuesday, United Flight 93, ultimately crashed in Pennsylvania, about 80 miles southeast of Pittsburgh.

"In a time of national crisis, the president has the power and it is both moral and legal for him to do such a thing," said Phillip J. Kolczynski, an aviation lawyer based in Santa Ana, Calif.

Anthony D'Amato, a professor at Northwestern University who specializes in international law, said some of the prospects presented by Bush's approval raised "cutting edge" legal issues if the government had indeed shot down the aircraft.

"The key issue would have been reasonableness. Was it reasonable that you shot it down as a precautionary measure to save more lives than would have been lost in the crash?" he said.